Character
Scylla and Charybdis
The two hazards of one narrow strait
The two hazards of a single narrow strait, and the reason the phrase means a choice with no good side. Scylla is a six-headed thing in a cliff that takes one man per head off a passing deck; Charybdis is a whirlpool that swallows the sea three times a day and spits it back. Circe tells Odysseus to hug Scylla's side and lose six men rather than lose the whole ship — and losing them, he says, was the most pitiful sight of the entire voyage.
Circe's advice — lose six men rather than the ship — is the poem's coldest piece of arithmetic, and Odysseus follows it.